Elements, Compounds and Mixtures


Roles:
Leader:Qian Hui
assistant leader:Yi De
Media manager:Matthew Yap
note taker:Ryan Tan
time keeper:Gladys


Activity 1

Definitions of

Element: - Consists of only one kind of atom.
             - Cannot be broken down into simpler type of matter by either physical means or chemical means.
             - Can exist as either atoms or molecules.
Example of an Element -> Actinium
(Picture taken from http://chemistry.about.com/od/periodictableelements/ig/Element-Photo-Gallery.--98/Actinium.-iQQ.htm)
Compounds: - Consists of atoms of two or more different elements bound together. 
                  - Can be broken down into simpler types of matter by chemical means. 
                  - Has properties that are different from its component's elements.
                  - Always contains the same ratio of its component atoms.
Example of a compound -> Water
(Picture taken from http://www.centralbasin.org/blog/wp-content/uploads/2011/03/water.jpg)
Mixtures: - Consists of 2 or more different elements or compounds physically intermingled.
              - Can be separated into its components by physical means. 
              - Often retains many of the properties of it components.
              - Same properties as its components.
Example of a mixture -> Air
(Picture taken from http://thumbs.dreamstime.com/thumblarge_555/1289426459CHtFwd.jpg)
Activity 2

 Definition/PropertiesAnalogy 
ElementsOne kind of atom , cannot be broken down by both physical and chemical means , exists as either atoms or molecules .Many cubes of cheese ( in wrapper ) of 2 different flavors . Each cheese cube is an element . 
Compounds2 or more different elements , can be broken down by chemical means , different properties from its component's elements , same ratio of its component's atoms .All the cubes of cheese ( in wrapper ) mixed together . Still can be separated .
Mixtures2 or more different elements or compounds , can be separated by physical means , retains properties of its components , same properties as its components .All the cheese ( without wrapper ) are melted . Cannot be separated anymore.


Activity 3 

Part II 

Appearance Observations
Iron The iron has a shiny outer appearance .
SulfurIt has a yellow outer surface and is powdery .
Iron(II) sulfide in Part 2 It cannot be attracted to the magnet because it has become a compound and it loses its original properties.


Questions 

1. Which of the results from the experiments show that the mixture of the iron fillings and sulfur has the properties of a mixture ?
     It can be separated into its components by using physical means and they retain the properties of their components.

2. What experimental evidence is there to show that a chemical reaction has taken place when the mixture of iron and sulfur is heated ?
     The compound loses its original property and cannot be separated by physical means , it also gives off a pungent smell.

Activity 4:
 
Left: Oxygen   Right: Hydrogen

Q1) Is water an element compound or mixture? Why?
It is a compound. As it is made up of 2 hydrogen molecules and 1 oxygen molecule.

Q2)What is purpose of the electrode?
 It is to pass an electric current through the water.

Q3) What do you observe at the electrode when switch is turn on?
Bubbles start to rise through the tube.

Q4) What do you think are the gases collected at the electrode?

a)the anode (positive electrode)
I think it is oxygen.

b)the cathode (negative electrode)
I think it is hydrogen.
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